Diabetic Foot Ulcer Biofilm Infection and Recurrence

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Abstract Diabetic foot ulcers (DFU) are one of the most common reason for hospitalization of diabetic patients and frequently it results in amputation of lower limbs. Of the one million people who undergo non-traumatic leg amputations annually worldwide, 75% are performed on people who have type 2 diabetes (T2DM). The risk of death at 10 years for a diabetic with DFU is twice as high as the risk for a patient without a DFU. The rate of amputation in patients with DFU is 38.4%. Infection is a common (>50%) complication of DFU. In those with DFU, 40% recur within one year after wound closure; 60% within 3 years, and 65% within 5 years. Thus, the strongest predictor of DFU is a previous foot ulcer. The proposed work rests on a series of pre-clinical and clinical findings laying the foundation to the hypothesis that biofilm infection of DFU compromises barrier function of the closed DFU. Such deficient closure paves the way to DFU recurrence. Biofilms are estimated to account for 60% of chronic wound infections. In the biofilm form, bacteria are in a dormant metabolic state. The standard clinical techniques like colony forming units (CFU) assay to detect infection may not detect biofilm infection. Thus, biofilm infection may be viewed as a silent maleficent threat in wound care. The proposed work is a two-center study – Indiana University and Stanford University – who were competitively funded with a pilot award by the NIDDK-DIACOMP mechanism to generate preliminary data on DFU closure and recurrence. The proposed work addresses a novel paradigm in DFU care that has never been tested in a fully powered patient- based study. Successful execution of the proposed work is likely to have direct impact on the current standards of wound care including re-defining the most important primary endpoint of wound care, wound closure itself. For the first time in a DFU patient-based study, mechanisms by which biofilm infection induces molecular mechanisms that compromise functional integrity of re-epithelialized DFU will be elucidated. In DFU care, the proposed work may identify that the current endpoint of wound closure (that does not account for any functional parameter) may be not the right time to stop caring for DFU. That such premature termination of care may be responsible for the high recurrence of DFU that is currently reported. The notion that continued care, until functional wound closure is achieved, is necessary to minimize recurrence and amputation would be of transformative value in the delivery of DFU care. This proposal, wholly based on the study of DFU patients seeks to conduct a two-centered robust clinical study testing whether wounds with a history of biofilm infection closes with deficient barrier function (Aim 2). Aim 3 tests whether such deficient wound closure which manifests as high TEWL is associated with greater wound recurrence. Aim 1 utilizes this patient-based study to address molecular mechanisms implicated in biofilm-induced loss of skin epithelial barrier integrity.